Powdery mildew.

Get new plants.

Based on advise I found on the internet , I sprayed a mixture of 2 cups milks and 3 tpsp baking soda (and 1 drop soap). The leaves now show yellow colored scaling :-(

Any suggestions on fungicides to use or other remedies??

Personally I haven't tried this, but try: four teaspoon baking soda, 1 teaspoon dawn, and one gallon of water. The recipe is from the link. You might want to spot test first.

Here is a link that might be useful: homemade fungicide recipe

Well, wash off what you have on there now.

It's not milk AND baking soda--- it's either OR. 1 part milk to 10 parts water.

or

1 TB baking soda and 1 tsp insecticidal soap to a gallon of water

Here's some more info.

Kevin

Here is a link that might be useful: Powdery Mildew

Powdery Mildew.

Milk/water is only good if you've have been spraying regularly before out break.

At this stage I suggest NEEM oil spray.